1. Field of the Invention
The present invention relates to a speech recognition system including a service processing center such as a switching system and a telephone terminal which are connected by a telephone network.
2. Description of the Related Art
In a first prior art speech recognition system, a speech recognizing function is incorporated into the switching system. As a result, it is possible to flexibly change the speech recognizing function. This will be explained later in detail.
In the first prior art speech recognition system, however, when noise such as crosstalk noise, signal distortion and so on are increased in accordance with the state of lines between the telephone network and the telephone terminal, the quality of propagating signals is deteriorated. As a result, the quality of speech signals received by the switching system are also deteriorated.
In a second prior art speech recognition system (see JP-A-68-76890), a speech recognizing function is incorporated into the telephone terminal. As a result, since the recognition result is transmitted in the form of digital data from the telephone terminal to the switching system, the quality of the recognition result is hardly deteriorated by the state of lines between the telephone network and the telephone terminal. This will be explained later in detail.
In the second prior art speech recognition system, it is impossible for the service processing center, i.e., the switching system to flexibly change the speech recognizing function. As a result, update services cannot be provided.
It is an object of the present invention to provide a speech recognition system capable of flexibly changing a speech recognition function without deteriorating the quality of recognition result.
According to the present invention, in a speech recognition system, a service processing center performs a service operation upon a speech recognition result and generates a speech response signal in accordance with the speech recognition result. A telephone terminal is connected via a telephone network to the service processing center. The telephone terminal receives a speech signal, recognizes the speech signal in accordance with a speech recognition software module, and acquires the speech recognition result. The speech recognition result is transmitted from the telephone terminal via the telephone network to the service processing center. The speech response signal is transmitted from the service processing center via the telephone network to the telephone terminal. The speech recognition software module is downloaded from the service processing center via the telephone network to the telephone terminal.